The present invention is directed to an airflow control system and particularly to an airflow control system that reduces turbulence.
There are many industrial applications that require a variable rate of airflow through a duct. One application of an airflow control system is a dryer in a vehicle wash system or car wash.
In a car wash, there are often dryers positioned at various locations along the vehicles path of travel. These dryers blow water off the vehicles, thereby substantially drying the vehicles. In such applications, a certain velocity of air is required to blow water off the vehicle surfaces. The air is typically provided by an air producer, blower, or air dryer. The air is then directed to the desired location by a duct having a duct exit or exhaust from which high velocity air exits. The velocity of the air decreases rapidly after it exits the duct. Therefore, the velocity of the air at the point it exits the duct is necessarily faster than the velocity required to blow the water off the surface of the cars.
If all vehicles had surfaces of the same height, the velocity of the air exiting the duct could be set to a predetermined rate, such that by the time the air reached the vehicle surface, it would have slowed to the proper speed. Most car washes, however, allow vehicles of greatly differing heights to enter the facility. If the exit velocity of the air from the duct is great enough to blow water off a low profile car, the same exit velocity of air could damage a high profile vehicle such as a van or a truck passing beneath the duct exit. Therefore, the airflow must be adjusted to correspond to the height of the surface from which the water is to be blown. Because the height of the blower is typically fixed a certain distance above the ground, to achieve a desired velocity of air at the surface of the vehicle, the exit velocity of air from the duct must be varied.
There are also other reasons that it would be advantageous to be able to adjust airflow. For example, since the soft-top of a convertible is easily damaged by maximum airflow, being able to reduce airflow would prevent the soft-top from being damaged. Another example is that being able to decrease airflow between vehicles would reduce power consumption of the system.
One way of providing an adjustable airflow has been to include a flat plate in the duct that can be rotated relative to the airflow to cause more or less of a blockage in the duct, thereby reducing or increasing the amount of airflow through the duct. The most open position would be when the major surface of the plate is parallel to the airflow and the most closed position would be when the major surface of the plate is perpendicular to the airflow. In the open position, the high speed of the airflow around the flat plate still causes significant turbulence, which decreases the efficiency of the system and increases the noise of the system. It is undesirable to have a decrease in efficiency and an increase in noise.
The transition between the air producer and the duct has also been problematic in that it tends to create turbulence. Generally the air exit of the air producer is smaller than the air entrance to the duct. Also, the air producer exit generally has a rectangular or square cross-section whereas the duct entrance generally has a round cross section. In an attempt to reduce turbulence, known systems have used a smooth gradation from the air producer exit to duct entrance. This smooth transition, however, has not been shown to significantly reduce or eliminate the turbulence.
Because older systems have inefficient airflow control systems, it would be desirable to be able to retrofit dryers in existing car washes with adjustable airflow control systems that neither reduce the efficiency of the system nor significantly increase the noise of the system.
Traditionally most car wash equipment, including dryers, has been installed using overhead arches. Although the arches allow for cabling and wiring to be easily run over the top of the car wash, the arches present a somewhat cluttered appearance and obstruct the view into the car wash. This is significant because it is important in the car wash industry that the machinery looks as clean and open as possible so as to attract customers to the car wash.
One difficulty with installation of traditional dryers in a car wash is determining where to position the duct exit or outlet of the air dryers relative to the vehicles to achieve optimal drying. When arches are used, the positioning of the air dryers becomes constrained by the position of the arch itself. Accordingly, there is a need for a modular air dryer system in which the duct exits can be located in any position relative to the vehicles passing through the vehicle wash system. Such a new positioning system would provide the car wash operator with increased flexibility in selecting the design configuration of the dryers, thereby increasing the efficiency of the dryers and making dryer installation easier and less expensive.
The invention claimed herein is directed to the inventions disclosed in U.S. Provisional Patent Application No. 60/129,109 and U.S. Design Patent Application No. 29/103,601, the subject matter of which is incorporated herein by reference.
An airflow control system of the present invention is positionable between an air producer and a duct exit. The airflow restricter includes an outer airflow restricter ring that has a central diameter. A pivot rod is rotatably positioned along the central diameter and an aerodynamic rotatable airfoil is secured about the pivot rod. Preferably, the system has an open position in which the airfoil being parallel to airflow and a closed position in which the airfoil being perpendicular to airflow. An actuator is optionally operatively connected to the pivot rod to permit rotation of the airfoil to be remotely actuated.
One preferred embodiment of the present invention may include an airflow transition between the air producer having a first-shaped air producer exit and the duct having a second-shaped duct entrance. The airflow restricter ring is positioned and secured between the air producer flange and the duct flange.
The foregoing and other objectives, features, and advantages of the invention will be more readily understood upon consideration of the following detailed description of the invention, taken in conjunction with the accompanying drawings.